Summary
Capitalizing on the inherent physical-chemical properties of CCBs facilitated strengthening of dike walls to prevent failure – evidenced by TVA’s Kingston spill. USEPA’s ‘high hazard listing’ for such CCB ponds relate to their proximity to habitation – an engineering failure concern, similar to levee and earthern dams. From an environmental regulatory standpoint CCBs are deemed Solid Waste not a hazardous waste. Coal Combustion Byproducts [CCBs] are presently regulated as Solid Waste [Subtitle D] under the Resource Conservation Recovery Act [RCRA]. Such classification promotes beneficial use by enders-users i.e. mitigating excessive liability. Stringent regulation, as Subtitle C (Hazardous Waste), would impose a perceived liability upon end-users; greatly reducing beneficial use opportunities. Mandatory use of synthetic liners – would not have prevented dike wall failure and fails to consider inherent engineering characteristics of CCBs.
Analysis
Forty-four coal ash storage sites near 26 communities have been targeted for inspection after federal officials identified the ponds as potential threats to nearby residents.
The storage ponds, which are used to store waste from coal-fired power plants, are in 10 states, according to a list released by the Environmental Protection Agency. The storage sites are similar to the one that flooded a neighborhood in Tennessee last year.
The 10 states, the number of sites, and communities are:
-North Carolina, 12 (Belmont, Walnut Cove, Spencer, Eden, Mount Holy, Terrell and Arden).
-Arizona, 9 (Cochise, Joseph City).
-Kentucky, 7 (Louisa, Harrodsburg, Ghent and Louisville).
-Ohio, 6 (Waterford, Brilliant and Cheshire).
-West Virginia, 4 (Willow Island, St. Albans, Moundsville, New Haven).
-Illinois, 2 (Havana, Alton).
-Indiana, 1 (Lawrenceburg).
-Pennsylvania, 1 (Shippingport).
-Georgia, 1 (Milledgeville).
-Montana, 1 (Colstrip).
USEPA Administrator Lisa Jackson promised, during her confirmation hearing, to promulgate stricter coal plant waste storage regulations. Capitalizing on the political opportunity of the TVA Kinston Spill will escalate with continued congressional hearings. Elected and appointed officials will find the coal industry an easy and demonized target to impose more stringent regulations.
These incidents and consequences should not indict coal-fired power plants or the electric utility industry; unexpected costs from ten to hundreds of million dollars and public embarrassment are sufficient punishments. How to avoid such upsets should be the focus of Coal Fired Power Plant operators and the Electric Utility Industry.
An Engineering Approach, reflecting demonstrated technology and recognizing CCPs chemical and geotechnical properties, should be embraced by the Electric Utilities with coal-fired power plants. Commitments to regulators to develop and implement this approach would curb excessive requirements. Electric utilities should capitalize upon the industry-wide knowledge and submit to USEPA as regulatory approaches are being developed.
If increased regulation translates into using CCBs in land disposal applications, with improved methods of placement [optimal compaction] and enhanced site management [capitalizing upon concrete-like behavior of coal combustion by-products], then such stronger regulation can be justified.
Consider the following uses of Power Plant Wastes to improve how they are land disposed:
PHYSICAL PROPERTIES OF FGD RESIDUE AND FLY ASH – Retrofitting Surface Impoundments as Grout to Strengthen Dike Walls
The particle size of FGD residue and fly ash shows this blend could be used as a grout material to stabilize existing CCB surface impoundment dike walls. When used as grout, the blend must be ability to penetrate between the interstitial soil spaces. Grouting existing soil dike wall would be about 90% less costly then slurry cutoff wall.
According to AECOM’s [TVA’s forensic geo-technical consultant] 6/25/09 Summary Report, a combination of the existence of an unusual bottom layer of ash and silt, the high water content of the wet ash, the increasing height of ash, and the construction of the sloping dikes over the wet ash were among the long-evolving conditions that caused a 50-year-old coal ash storage pond breach and subsequent ash spill at TVA’s Kingston Fossil Plant on December 22, 2008. Retrofit of surface impoundments, using FGD residue and fly ash and, where required, a cementious additive would prevent similar dike wall failures.
RESIDUE MANAGEMENT – Placement – Landfill Methodology
The inherent pozzolanic-like behavior of lime-laden CCBs enables achieving improved geo-technical properties i.e. strength, permeability. Achieving liner-like permeabilities, by capitalizing upon CCB’s inherent characteristics and applying Proper Placement Control, achieves cost savings of 65% over traditional disposal methods e.g. synthetic liners.
DEMONSTRATION PROGRAM – Landfill and Surface Impoundment Embankments
Considering the inherent engineering properties of CCBs justifies using this material to form surface impoundment dike walls. Approximately 27.5 million tons of CCBs are retained in surface impoundments. Preventing failure of these dike walls represents a primary issue for discussions between the electric utility industry and regulators. A demonstration program, based on laboratory and bench-scale testing, would indicate industry willingness to address future requirements in a cost-effective manner.
The electric utility industry with their trade and research organizations are urged to commit to conducting such programs (demonstrating the application of CCBs in land disposal) – showing a ‘good faith’ effort to cooperate with regulatory and addresses recent CCB disposal upsets.
REFERENCES
S. Dewan; “Hundreds of Coal Ash Dumps Lack Regulation”; The New York Times; January 7, 2009
Goodwin, R.W.; Combustion Ash/Residue Management ‑ An Engineering Perspective; Noyes Publications/William Andrew Publishing; Mill Road, Park Ridge NJ 1993 (ISBN: 0‑8155‑1328‑3) (Library of Congress Catalog Card No.: 92‑47240)
